Red cell folate and plasma homocysteine in preterm infants

The supplementation of preterm infants with folic acid is routine practice in many neonatal units. However, the advent of preterm formula milks and breast milk fortifiers have increased folic acid intake. We measured red cell folate in preterm infants who received preterm formula milks and breast milk fortifiers to determine whether additional folic acid supplementation was still required. A potential benefit of folic acid supplementation is reduction of plasma total homocysteine (tHcy). tHcy appears to have a linear association with the risk of atherothrombotic vascular events in adults but its role in intraventricular haemorrhage and associated white matter damage in preterm infants is not known. As there is little information regarding tHcy in preterm infants, we also measured tHcy in this study.

Red cell folate and tHcy were measured at 1 and 4 weeks of age and before discharge in 28 consecutive infants <34 weeks' gestation. Factors which may have affected folate and homocysteine status were recorded.

Red cell folate ranged between 266 and 1,513 ng/ml and deficiency (<140 ng/ml) was not observed in any sample. Red cell folate concentration tended to increase with increasing age. tHcy ranged from 0.8 to 12.2 micromol/l and fell within the 'normal' range for fasting adults.

Preterm formula milks and breast milk fortifiers provide sufficient folic acid to prevent folate deficiency in preterm infants. Although tHcy fell within the 'normal' range for fasting adults, more research is needed to determine optimal concentration of tHcy for preterm infants.